During the Course of Working on a Complex Project,a Client

During the course of working on a complex project,a client shared confidential information with its CPA.The CPA did a superb job,but the client,however,has never paid the CPA for her services.The CPA anticipates that,if she initiates a lawsuit to collect the amount due,the client will claim that the task was simple and the CPA's performance was below standard.If the CPA wants to introduce the nature of the work done as evidence in her court action to collect unpaid fees:

A) She may not do so because she has a duty to not reveal confidential information
B) She may do so because the complexity of the tasks performed by her is a critical fact in her lawsuit
C) She may not reveal confidential information unless the court issues a protective order
D) She may discuss confidential information only if her client reveals it first or if she obtains the consent of her client, the opposing party